JPWO2012085998A1 - Hydraulic control device - Google Patents

Abstract

Provided is a hydraulic control device capable of preventing a transient hydraulic response delay at the time of restart when air is mixed into pressurized oil. In a hydraulic control device configured to open a supply valve and supply pressure oil from a hydraulic source to a hydraulic chamber that performs a predetermined operation by supplying pressure oil, during a stop period in which the supply valve is closed Estimating means (step S2) for estimating the amount of air mixed in with respect to the hydraulic pressure, and estimating means for estimating the amount of pressure oil supplied to the hydraulic chamber when the supply valve is opened again to supply the hydraulic oil to the hydraulic chamber again Correction means (steps S3 and S14) for correcting based on the estimation result of

Description

  The present invention relates to an apparatus for controlling hydraulic pressure supplied to and discharged from various actuators.

  Hydraulic pressure is widely used in various transport equipment and industrial machines because power and control information are transmitted by the pressure and the position can be controlled by the amount. As an example, European Patent No. 0985855 describes a hydraulic control device in an automatic transmission for a vehicle. The automatic transmission described in the specification of European Patent No. 0985855 is a belt-type continuously variable transmission, in which a gear ratio is appropriately set by changing a groove width of a pulley by hydraulic pressure, and a belt is sandwiched. In order to set a predetermined transmission torque capacity, hydraulic pressure is supplied to one of the pulleys on the driving side and the driven side. The hydraulic control device described in the specification of European Patent No. 0985855 supplies a hydraulic pressure to a hydraulic chamber of each pulley around which a belt is wound, and as a control valve for discharging the hydraulic pressure from the hydraulic chamber of each pulley, A valve that closes the oil passage almost completely is used. Therefore, in the hydraulic control apparatus described in the specification of European Patent No. 0985855, by closing these valves, the hydraulic pressure is confined in the hydraulic chambers of the pulleys, and the previous transmission ratio and belt clamping pressure can be maintained. it can.

  In a transmission that transmits torque with a frictional force, such as a continuously variable transmission described in the specification of European Patent No. 0985855, the frictional force or the transmission torque capacity based on the frictional force changes depending on the hydraulic pressure. That is, when the hydraulic pressure is relatively low with respect to the torque input to the transmission, the frictional force, that is, the transmission torque capacity is insufficient and slipping occurs. Thus, for example, a control device described in Japanese Patent Application Laid-Open No. 2004-316843 is configured to reduce engine output torque when slippage is detected by a belt-type continuously variable transmission.

  As described in European Patent No. 0985855, if the supply side and the discharge side valves are closed to confine the oil pressure, the previous operating state can be maintained. When the vehicle is stopped and the hydraulic pump is stopped accordingly, the operation state such as the gear ratio and the transmission torque capacity at that time can be maintained. When restarting from the stopped state, the operating state required after the restart is often not the same as the state before the stop, so the hydraulic source such as a restarted hydraulic pump supplies hydraulic pressure to a predetermined actuator or hydraulic chamber. To set the required operating state. When hydraulic pressure is supplied to the actuator, hydraulic chamber, etc. in accordance with the restart in this way, the pressure oil that has already been confined is added to the pressure oil that has been confined, and the pressure gradually increases. This tendency varies depending on the situation of pressure oil being trapped.

  That is, even in a hydraulic control device configured to be able to perform so-called closing control, inevitable hydraulic pressure leakage occurs in the valves and various seal portions, and air is mixed into the pressure oil. Oil (pressure oil) used in the hydraulic control device is an incompressible fluid, and various control values are determined on the premise of it. For example, when air is mixed in the pressure oil, the bubbles inside the pressure oil are pressurized. Therefore, the pressure oil mixed with air functions as a compressive fluid as a whole. Therefore, when restarting, even if pressure oil is supplied from the hydraulic source to the actuator or the hydraulic chamber, the pressure oil is initially consumed to compress the air bubbles. A situation that cannot be obtained occurs. For example, in the belt type continuously variable transmission described in the above-mentioned European Patent No. 0985855 and Japanese Patent Application Laid-Open No. 2004-316843, the belt clamping pressure at the time of restart is insufficient and the belt slips. Or the durability may decrease due to this. The device described in Japanese Patent Application Laid-Open No. 2004-316843 is configured to reduce the engine torque when belt slip is detected, so the engine torque is reduced to converge the belt slip. Even if it is possible, in order to reduce the engine torque, it is essential that belt slip occurs, and such belt slip cannot be avoided or suppressed in advance.

  The present invention has been made paying attention to the technical problem described above, and provides a hydraulic control device capable of avoiding or suppressing a control response delay even when air is mixed into pressure oil. It is the purpose.

  In order to achieve the above object, the present invention provides a hydraulic system configured to open a supply valve and supply pressure oil from a hydraulic source to a hydraulic chamber that performs a predetermined operation when the pressure oil is supplied. In the control device, when the supply valve is reopened and the supply of pressure oil to the hydraulic chamber is performed again by estimating means for estimating the amount of air mixed into the hydraulic pressure during the stop period in which the supply valve is closed And a correction means for correcting the amount of pressure oil supplied to the hydraulic chamber based on the estimation result by the estimation means.

  Further, according to the present invention, in the above invention, a pressure reducing valve that reduces a hydraulic pressure of a hydraulic circuit that supplies pressure oil to the hydraulic chamber, and a pressure oil that is supplied to the hydraulic chamber at the time of restarting the supply of the pressure oil. Hydraulic pressure limiting means for opening the pressure reducing valve and reducing the hydraulic pressure of the hydraulic circuit when restarting when the hydraulic pressure of the hydraulic circuit exceeds a predetermined upper limit hydraulic pressure by correcting the amount by the correction means; The hydraulic control device further includes the hydraulic control device.

  Further, according to the present invention, in the above invention, the correction means includes means for increasing the amount of pressure oil supplied to the hydraulic chamber at the time of restart as the air mixing amount estimated by the estimation means increases. A hydraulic control device including the hydraulic control device.

  Still further, according to the present invention, in any one of the above-described inventions, the estimation unit includes a unit that estimates an amount of air contamination based on the stop period and estimates a larger amount of mixture as the stop period is longer. Is a hydraulic control device characterized by

  Furthermore, this invention corrects the amount of the pressure oil corrected by the correction means in any one of the above-mentioned inventions based on any one of the oil temperature, the pressure of the outside air, and the state of deterioration of the hydraulic pressure. The hydraulic control apparatus further includes a next correction unit.

  According to the present invention, in any one of the above-described inventions, the hydraulic chamber is provided in a transmission mechanism that sets a transmission torque capacity according to a supplied hydraulic pressure, and the air mixing amount estimated by the estimation unit is set. When the correction amount of the pressure oil amount that can be corrected by the correction means is insufficient with respect to the correction amount of the pressure oil supplied to the hydraulic chamber at the time of restart determined based on The hydraulic control device further includes a torque reduction means for reducing the input torque.

  According to this invention, when the stop state in which the supply valve is closed continues, the amount of air mixed into the pressure oil is estimated based on the stop period, and the supply valve is reopened to supply the hydraulic oil to the hydraulic chamber. In doing so, the supply amount of pressure oil is corrected based on the estimation result. Therefore, if air is mixed in the pressure oil and the pressure is difficult to increase, the increased amount of pressure oil is supplied at the beginning of the restart, so there is no delay in the increase in oil pressure in the hydraulic chamber. Alternatively, the delay in the pressure rise is suppressed, and the hydraulic control with good responsiveness can be performed.

  In addition, even if the pressure of the hydraulic circuit that supplies the hydraulic oil to the hydraulic chamber is increased by providing a pressure reducing valve that is opened at the upper limit hydraulic pressure, if a situation in which the pressure increases beyond the upper limit occurs, the pressure reducing valve Since the hydraulic pressure is released by this, it is possible to prevent or suppress an excessive increase in the pressure in the hydraulic chamber.

  Furthermore, if the increase amount of the pressure oil supply amount is increased as the amount of air mixed into the pressure oil increases, the response delay of the hydraulic control can be avoided or suppressed more reliably.

  In the present invention, the amount of mixed air can be estimated based on the stop period of the supply valve. More specifically, it can be estimated that the longer the stop period, the greater the amount of mixed air. it can.

  Furthermore, the correction amount of the pressure oil supplied at the time of restart can be configured to be further corrected based on the oil temperature, the pressure of the outside air, the degree of deterioration of the pressure oil, and the like. The hydraulic response at the time of restart can be further improved.

  In the present invention, when the amount of correction by the correction means is insufficient and the influence of air mixing cannot be corrected sufficiently and sufficiently, the input torque to the transmission mechanism is reduced, so that the transmission torque capacity for the input torque in the transmission mechanism is reduced. An excessive shortage can be avoided.

It is a flowchart for demonstrating an example of the control performed with the control apparatus which concerns on this invention. It is a map which shows the relationship between stop elapsed time and a basic correction current. It is a figure which shows the relationship between the electric current of a pressure increase valve, and the flow volume of pressure oil. It is a flowchart for demonstrating the other example of the control performed with the control apparatus which concerns on this invention. It is a diagram which shows the relationship between the pressure difference before and behind a pressure-reduction valve, and an electric current. It is a flowchart for demonstrating the further another example of the control performed with the control apparatus which concerns on this invention. It is a schematic diagram which shows simply an example of the hydraulic circuit which can apply this invention.

  The present invention can be applied to a hydraulic control device in a vehicle, a construction machine, or various industrial devices, and as an example, it can be applied to a hydraulic control device in a belt type continuously variable transmission for a vehicle. In this type of belt type continuously variable transmission, a belt is wound around a driving pulley and a driven pulley whose width can be changed by hydraulic pressure, and hydraulic pressure is supplied to or discharged from a hydraulic chamber of one pulley. The belt groove is changed by changing the width of the belt groove along with the width of the belt groove in the other pulley, and the belt is moved by supplying hydraulic pressure corresponding to the input torque to the hydraulic chamber in the other pulley. It is comprised so that the clamping pressure to clamp may be set. FIG. 7 schematically shows an example of a hydraulic control device that supplies and discharges hydraulic pressure to one pulley 1 and the pulley 1 in this type of belt-type continuously variable transmission. The pair of pulleys around which the belt 2 is wound and the hydraulic control device thereof are substantially the same as the configuration shown in FIG.

  The pulley 1 shown in FIG. 7 includes a fixed sheave 1a integrated with the pulley shaft 3, and a movable sheave 1b fitted to the pulley shaft 3 so as to approach and leave the fixed sheave 1a. The surfaces of the sheaves 1a and 1b facing each other are formed in a tapered shape, and a belt groove 4 around which the belt 2 is wound is formed between the tapered surfaces. A hydraulic chamber 5 is formed on the back side (opposite side of the tapered surface) of the movable sheave 1b. By supplying hydraulic pressure to the hydraulic chamber 5, the movable sheave 1b is pushed to the fixed sheave 1a side and the belt 2 Is sandwiched between the fixed sheave 1a. The hydraulic pressure supplied to the hydraulic chamber 5 is controlled so that the width of the belt groove 4 becomes a width that sets the target speed ratio in a pulley that is controlled to set the speed ratio, and the transmission torque capacity is reduced. The pulley to be set is controlled so as to generate a belt clamping pressure corresponding to the input torque.

  An oil passage 6 communicating with the hydraulic chamber 5 is formed along the central axis of the pulley shaft 3, and a hydraulic pressure source 8 is connected to the oil passage 6 via a pressure increasing valve 7 corresponding to a supply valve in the present invention. , And a pressure reducing valve 9 that exhausts pressure from the hydraulic chamber 5 to reduce the hydraulic pressure is communicated with the oil passage 6. More specifically, the hydraulic power source 8 includes a hydraulic pump 11 that is driven by an engine 10 that is a driving force source of the vehicle or a motor (not shown), and an accumulator 12 that stores the hydraulic pressure generated by the hydraulic pump 11. A pressure sensor 13 is connected to the accumulator 12.

  A pressure increasing valve 7 is provided in the middle of a hydraulic circuit 14 that connects the hydraulic source 8 and the oil passage 6 formed in the pulley shaft 3. The pressure increasing valve 7 is a valve that is electrically controlled to control the supply of pressure oil to the hydraulic chamber 5 by opening and closing the port. The pressure increasing valve 7 is an electromagnetic valve whose opening degree or flow rate changes according to the current value. In addition, it is constituted by an electromagnetic valve such as a duty valve that controls the flow rate according to the duty ratio. In the example shown in FIG. 7, the pressure increasing valve 7 is configured by a poppet type valve whose opening degree changes according to the current value. A hydraulic pressure sensor 15 that detects the hydraulic pressure in the hydraulic circuit 14 is provided. Further, the pressure reducing valve 9 described above is a valve that is electrically controlled to open and close the port. In the example shown in FIG. 7, the opening degree changes according to the current value in the same manner as the pressure increasing valve 7 described above. It is composed of poppet type valves. The pressure reducing valve 9 is connected to a hydraulic circuit 14 between the pressure increasing valve 7 and the oil passage 6 of the pulley shaft 3. Each of the pressure increasing valve 7 and the pressure reducing valve 9 is configured to be appropriately controlled by an electronic control device (not shown). In addition, torque is input to the pulley 1 directly or indirectly from the engine 10.

  Since each of the pressure increasing valve 7 and the pressure reducing valve 9 is configured to be in a closed state when the energization is interrupted, in the stop state where the energization is stopped, such as when the vehicle is stopped, the pulley 1 Pressure oil is confined in the hydraulic chamber 5, and the immediately preceding operation state is maintained. However, air is mixed into the pressure oil due to inevitable leakage. Therefore, since the so-called rigidity of the pressure oil is reduced at the time of restart, the hydraulic control device according to the present invention corrects the amount of pressure oil supplied to the hydraulic chamber 5 of the pulley 1 at the time of restart. It is configured. FIG. 1 is a flowchart for explaining an example of the control, and this routine is repeatedly executed every short time.

  First, a vehicle equipped with the belt type continuously variable transmission is started from a stopped state, and it is determined whether or not the travel that is currently being executed is the first travel after the start (step S1). This determination can be made based on, for example, that the main switch has been switched from OFF to ON. If the determination is affirmative in step S1 because the vehicle has been restarted for traveling again, the period during which the vehicle has stopped, that is, the elapsed time Tstp from the previous stop is calculated (step S2). The elapsed time Tstp can be obtained by, for example, a timer that starts when the main switch is turned off.

  Next, the basic correction current Iaddb is obtained based on the elapsed time Tstp (step S3). The basic correction current Iaddb is a current value for correcting the amount of oil supplied to the hydraulic chamber 5 described above. In addition, the oil amount is corrected to correct the hydraulic rigidity that has changed along with the air mixed into the pressure oil while each of the pressure increasing valve 7 and the pressure reducing valve 9 is closed and stopped. It is. The change in the hydraulic rigidity or the change in the hydraulic response due to the air mixing occurs according to the air mixing amount, and the air mixing amount is an amount corresponding to the elapsed time of the stop state. Furthermore, the amount of air mixed in according to the elapsed time is not theoretically determined, and there are strong factors that are determined according to the actual state such as the configuration of the hydraulic control device. Therefore, the relationship between the elapsed time of the stop state and the basic correction current Iaddb can be measured in advance based on experiments or the like, and prepared as a map, for example. An example of the map is shown in FIG.

  After the basic correction current Iaddb is calculated in step S3, or in parallel therewith, it is determined whether or not the oil temperature toil is equal to or less than a predetermined oil temperature correction threshold tth (step S4). This determination step is for determining whether or not the viscosity of the oil is high enough to affect the supply amount of the hydraulic pressure. Therefore, the oil temperature correction threshold value tth is the extent to which the viscosity of the oil affects the hydraulic control. Set to a low temperature. This can be determined in advance by experiments or simulations. When the oil temperature toil is equal to or less than the oil temperature correction threshold value tth and the determination in step S4 is affirmative, the value of the oil temperature correction gain Kt is set to a predetermined value α (step S5). ). This oil temperature correction gain Kt is a so-called correction coefficient for correcting the response delay of the hydraulic pressure due to the high viscosity of the oil. Therefore, the predetermined value α increases the supply amount of the pressure oil or has been described above. It is preset so as to increase the opening of the pressure increasing valve 7. Specifically, it is a numerical value larger than “1”. The values of the oil temperature correction threshold value tth and the oil temperature correction gain Kt may be constant values, but both of these values are variables, and the lower the oil temperature correction threshold value tth, the larger the oil temperature correction gain Kt. A format such as a map can be determined in advance.

  If the oil temperature toil exceeds the oil temperature correction threshold value tth and is determined negative in step S4, the oil temperature correction gain Kt is set to “1” (step S6). That is, if the oil temperature toil is high to some extent, it is considered that the viscosity is within the range assumed in the design and does not particularly affect the oil pressure control. The secondary correction is not performed.

  After executing the control in step S5 or step S6, it is determined whether or not the atmospheric pressure Poil is equal to or lower than the atmospheric pressure correction threshold Pth (step S7). The atmospheric pressure Poil may be directly measured with a barometer, or may be calculated from the altitude of the current position stored in the navigation system. The determination in step S7 is for determining whether or not the external air pressure is low enough to affect the hydraulic pressure of the hydraulic chamber 5 described above. Therefore, the atmospheric pressure correction threshold value Pth affects the hydraulic pressure of the hydraulic chamber 5. The air pressure is set low enough to exert This can be determined in advance by experiments or simulations. If the atmospheric pressure Poil is equal to or less than the atmospheric pressure correction threshold value Pth, and a positive determination is made in step S7, the value of the atmospheric pressure correction gain Kp is set to a predetermined value β (step S8). This atmospheric pressure correction gain Kp is a so-called correction coefficient for coping with the fact that the amount of air that can be dissolved in the oil decreases due to the low external pressure applied to the hydraulic chamber 5 and is likely to precipitate as bubbles. The predetermined value β is set in advance so as to increase the supply amount of the pressure oil or increase the opening degree of the pressure increasing valve 7 described above. Specifically, it is a numerical value larger than “1”. Note that the values of the atmospheric pressure correction threshold value Pth and the atmospheric pressure correction gain Kp may be constant values, but both of these values are variables, and the map is such that the lower the atmospheric pressure correction threshold value Pth, the larger the atmospheric pressure correction gain Kp. Etc. can be determined in advance.

  If the determination is negative in step S7 because the atmospheric pressure Poil exceeds the atmospheric pressure correction threshold Pth, the atmospheric pressure correction gain Kp is set to “1” (step S9). That is, if the atmospheric pressure Poil is high to some extent, it is considered that the degree of increase in the hydraulic pressure of the hydraulic chamber 5 with respect to the supply amount of pressure oil is within the range assumed in the design and does not particularly affect the hydraulic control. As described above, the substantial secondary correction based on the atmospheric pressure Poil is not performed.

  After executing the control in step S8 or step S9, the degree of oil deterioration is determined (step S10). The oil of the above hydraulic control device is used in a sealed state, but it is used in harsh conditions such as being stirred and heated and cooled. Characteristics such as gender change. The degree of such deterioration can be determined by the degree of increase in pressure when pressurized, the flow rate when passing through an orifice, etc., but the deterioration progresses as the service period becomes longer, especially pressure Deterioration progresses as the substantial use time such as adding or flowing is increased. Accordingly, in step S10 in the example shown in FIG. 1, the distance traveled by the vehicle equipped with the continuously variable transmission after the oil of the belt type continuously variable transmission is changed (hereinafter simply referred to as the travel distance). It is determined whether Doil is less than or equal to the oil deterioration correction threshold value Dth. Therefore, the oil deterioration correction threshold value Dth is set to a distance at which the oil deteriorates to the extent that the oil pressure of the hydraulic chamber 5 is affected. This can be determined in advance by experiments or simulations.

  If the travel distance Doil is equal to or greater than the oil deterioration correction threshold value Dth and a positive determination is made in step S10, the value of the oil deterioration correction gain Kd is set to a predetermined value γ (step S11). The oil deterioration correction gain Kd is a so-called correction coefficient for coping with a decrease in defoaming performance due to deterioration of the pressure oil in the hydraulic chamber 5 when pressure oil is supplied to the hydraulic chamber 5. The predetermined value γ is set in advance so as to increase the supply amount of pressure oil or increase the opening degree of the pressure increasing valve 7 described above. Specifically, it is a numerical value larger than “1”. Note that the values of the oil deterioration correction threshold Doil and the oil deterioration correction gain Kd may be constant values. However, both of these values are variables, and the oil deterioration correction gain Kd increases as the oil deterioration correction threshold Doil increases. A format such as a map can be determined in advance.

  On the other hand, if the travel distance Doil is less than the oil deterioration correction threshold Dth and a negative determination is made in step S10, the oil deterioration correction gain Kd is set to “1” (step S12). In other words, if the travel distance Doil is still short, the oil is not particularly deteriorated, and the degree of increase of the hydraulic pressure in the hydraulic chamber 5 with respect to the supply amount of pressure oil is within the range assumed in the design, and particularly in hydraulic control. Since it is considered that the influence does not occur, as described later, the substantial secondary correction based on the travel distance Doil, that is, the deterioration of the oil is not performed.

  Note that the order of the determinations in step S4, step S7, and step S10 described above is not limited to the order shown in FIG. 1, and the order may be changed as appropriate or selected as necessary. .

  If the determination is affirmative in step S1 because it is the first run after start-up, the basic correction current Iaddb and the correction gains Kt, Kp, Kd are obtained as described above, and their correction gains. The basic correction current Iaddb is corrected by Kt, Kp, Kd (step S13). In the example shown in FIG. 1, the final correction current Iaddf is calculated by multiplying the basic correction current Iaddb by the respective correction gains Kt, Kp, Kd. In that case, each of the correction gains Kt, Kp, Kd is doubled according to the value obtained by multiplying the other correction gains Kt, Kp, Kd, so that the respective correction gains Kt, Kp, Kd are The value is set to allow for such an increase. Instead of such correction, the correction gains Kt, Kp, and Kd may be added, and the sum is multiplied by the basic correction current Iaddb to obtain the final correction current Iaddf.

  Then, the booster valve final command current Iaplf is obtained by adding the final correction current Iaddf calculated in step S13 to the booster valve basic command current Iaplb (step S14). Here, the pressure increasing valve basic command current Iaplb is a current for obtaining a hydraulic pressure determined based on a target speed ratio and belt clamping pressure (that is, transmission torque capacity) to be set at the first travel after the start. That is, the amount of hydraulic pressure or pressure oil in the hydraulic chamber 5 is determined based on the target gear ratio and target clamping pressure, and the opening of the pressure increasing valve 7 can be obtained based on the amount of hydraulic pressure or pressure oil. Since the current value corresponding to the degree is determined by the specifications or characteristics of the booster valve 7, based on these relationships, the booster valve basic command current Iaplb is obtained based on the target speed ratio or the target clamping pressure. The pressure increase valve basic command current Iaplb is obtained on the premise that the oil exhibits the behavior assumed in the design, so it does not take into account the effects of temporary factors such as air contamination and viscosity increase. . Therefore, in step S14, the final pressure increase valve final command current Iaplf is obtained by adding the final correction current Iaddf to the pressure booster basic command current Iaplb.

  If a negative determination is made in step S1 described above, that is, if the current travel is not the first travel after the start, the value of the final correction current Iaddf is set to “0” (step S15). Then, the process proceeds to step S14. That is, the current value is not corrected, and the booster valve basic command current Iaplb is set to the booster valve final command current Iaplf.

  FIG. 3 is a characteristic diagram showing the relationship between the current I and the flow rate Q of the pressure increasing valve 7 in the specific example shown in FIG. 7. When the control shown in FIG. At that time, the basic correction current Iaddb based on the previous stop period is subjected to a so-called secondary correction based on either the oil temperature, the atmospheric pressure, or the deterioration state, and the final correction current Iaddf thus obtained is added to the pressure increasing valve. It is added to the basic command current Iaplb. Accordingly, the opening of the pressure increasing valve 7 is increased by an amount corresponding to the added final correction current Iaddf, so that the hydraulic chamber 5 is supplied with an amount of pressure oil that has been increased and corrected according to the final correction current Iaddf. The The increase correction of the supply amount is based on correction based on the amount of mixed air that is handled as the elapsed time of the stop state, and this is secondarily corrected in the state of oil temperature, pressure or oil deterioration, Even if air is mixed in the pressure oil, the volume reduction due to the contraction (compression) of the mixed air can be compensated by the supply amount of the pressure oil, and the response delay of the hydraulic pressure can be avoided or suppressed. Since the supply amount of pressure oil can be increased before the torque is applied at the time of restart in this way, in particular, in the belt-type continuously variable transmission described above, The belt slip resulting from it can be prevented or suppressed reliably.

  The above-described control example shown in FIG. 1 is a control example in which the supply amount of the pressure oil via the pressure increasing valve 7 is corrected for pressure increase. In this control, the correction amount is obtained based on data such as the stop period and the oil temperature. Yes. Therefore, the control is similar to the so-called feedforward control, and actual hydraulic excess / deficiency is not fed back to the correction amount. In other words, there is no possibility that the hydraulic pressure becomes excessive for some reason. Therefore, in order to maintain durability, it is preferable that the maximum pressure be limited.

  FIG. 4 shows an example of the control, and the control example shown here is configured to limit the hydraulic pressure of the hydraulic chamber 5 or the hydraulic circuit 14 communicating therewith to the maximum pressure. Note that the control example shown in FIG. 4 is configured to execute so-called guard control following the control shown in FIG. 1 described above. Therefore, the same steps as the control step shown in FIG. Similar step numbers are assigned and description thereof is omitted. When the booster valve final command current Iaplf is obtained in step S14, the maximum guard value Pmxgrd is calculated (step S16). The maximum guard value Pmxgrd is a maximum pressure set in consideration of the durability of the hydraulic chamber 5 or the hydraulic circuit 14 described above, and can be determined in advance based on experiments and simulations.

  Next, the valve opening current Irelopn corresponding to the maximum guard value Pmxgrd is calculated (step S17). FIG. 5 is a characteristic diagram showing the relationship between the valve opening current of the pressure reducing valve 9 and the front-rear differential pressure Pout. The pressure reducing valve 9 is configured to apply an elastic force in the valve closing direction and reduce the elastic force by an electromagnetic force generated by energization. Further, since the pressure applied to the pressure reducing valve 9 is the hydraulic pressure of the hydraulic chamber 5 or the hydraulic circuit 14 and the atmospheric pressure on the drain side, the front-rear differential pressure Pout is eventually detected by the hydraulic sensor 15. This is the hydraulic pressure of the hydraulic chamber 5 or the hydraulic circuit 14. Therefore, as shown in FIG. 5, when the current increases, the pressure reducing valve 9 opens with a small differential pressure. Therefore, the valve opening current Irelopn is adjusted to the maximum guard value Pmxgrd from the characteristic diagram shown in FIG. Current value. The valve opening current Irelopn thus obtained is set as the pressure reducing valve final instruction current Irelf (step S18).

  Therefore, if the control is performed as shown in the flowchart of FIG. 4, the supply amount of the pressure oil to the hydraulic chamber 5 is corrected to be increased by the pressure increasing valve 7, and as a result, the pressure in the hydraulic circuit 14 and the hydraulic chamber 5 becomes the maximum guard value Pmxgrd. When the pressure reaches, the pressure reducing valve 9 opens to discharge the pressure oil, and it is avoided that the hydraulic pressure in the hydraulic chamber 5 or the hydraulic circuit 14 increases further. Therefore, the durability of the continuously variable transmission, which is a transmission mechanism, is improved by preventing the pressure in the hydraulic chamber 5 or the load with which the pulley 1 sandwiches the belt 2 from being excessively increased, or the durability is reduced. Can be suppressed.

  Contrary to the excessive hydraulic pressure in the hydraulic chamber 5 or the hydraulic circuit 14 described above, there is a case in which the decrease in the hydraulic response due to the mixing of air cannot be compensated by the increase correction of the pressure oil. In such a case, the input torque to the continuously variable transmission can be reduced to avoid a relative shortage of hydraulic pressure. FIG. 6 is a flowchart showing an example of the control. Like the routines shown in FIG. 1 and FIG. 4, the control is repeatedly executed every short time, and subsequently or in parallel with those routines. In the routine shown in FIG. 6, first, an elapsed time Tstp since the stop, that is, an elapsed time Tstp from the previous stop is calculated (step S21). This is a control step similar to step S2 shown in FIG. 1 or FIG.

  Next, it is determined whether or not the elapsed time Tstp has exceeded a predetermined threshold value Tth (step S22). The elapsed time threshold value Tth is used to determine that the amount of air mixed into the pressure oil increases to such an extent that the response delay cannot be compensated by the pressure oil increase correction, and is therefore set to a large value. . Specifically, it can be determined in advance based on results of experiments and simulations. If a negative determination is made in this step S22, the amount of air mixed in with the pressure oil remains to a level that can be accommodated by the pressure oil increase correction, so this routine is temporarily terminated without performing any particular control. To do.

  On the other hand, if the determination is affirmative in step S22 because the engine has been stopped for a long period of time exceeding the threshold value Tth, control for reducing the input torque to the continuously variable transmission is executed ( Step S23). Specifically, when the engine 10 is provided with an electronic throttle valve (electric throttle), when the accelerator pedal is depressed for starting and there is a request to increase the output of the engine 10, the opening of the electronic throttle valve Is subjected to a smoothing process (electrical throttling control ON) to delay the increase in engine torque and cause the engine torque to transition at a relatively low torque. The control for reducing the input torque to the continuously variable transmission may be, for example, control for reducing the amount of fuel supplied to the engine 10 or control for retarding the ignition timing in the case of a gasoline engine.

  Therefore, if the control as shown in FIG. 6 is performed, the control for increasing the supply amount of the pressure oil reduces the input torque when the hydraulic pressure control due to the air mixture cannot be compensated. For example, when starting in a continuously variable transmission Since the input torque is small even if the transmission torque capacity is small, belt slipping can be avoided or suppressed in advance.

  Here, the relationship between the present invention and the above specific example will be briefly described. The functional means for executing the control in step S2 described above corresponds to the estimation means in the present invention, and the control in step S3 or step S14. The functional means for executing this corresponds to the correcting means in the present invention. Furthermore, the functional means for executing the control in step S18 corresponds to the hydraulic pressure limiting means in the present invention, and the functional means for executing the control in steps S4 to S13 corresponds to the secondary correction means in the present invention. And the functional means which performs control of step S23 shown in FIG. 6 is equivalent to the torque reduction means in this invention.

  The present invention is not limited to the specific examples described above, and can be applied to hydraulic control devices other than the hydraulic control for continuously variable transmissions. Further, the valve for controlling the supply amount of pressure oil may be a duty solenoid valve. In this case, the duty ratio is controlled instead of the current control.

[0003]
In order to lower the belt, it is essential that belt slip occurs, and such belt slip cannot be avoided or suppressed in advance.
SUMMARY OF THE INVENTION [0006]
The present invention has been made paying attention to the technical problem described above, and provides a hydraulic control device capable of avoiding or suppressing a control response delay even when air is mixed into pressure oil. It is the purpose.
[0007]
In order to achieve the above object, according to the present invention, a pulley in a belt-type continuously variable transmission includes a hydraulic chamber, and a width of a groove around which the belt is wound according to the hydraulic pressure of the hydraulic chamber, or sandwiching the belt. And a supply valve for supplying hydraulic pressure from a hydraulic pressure source to the hydraulic chamber, and the hydraulic force acting in the valve closing direction is reduced by an electromagnetic force corresponding to the valve opening current. In a hydraulic control device provided with a pressure reducing valve for reducing the hydraulic pressure of a hydraulic circuit for supplying pressure oil to the chamber, the amount of air mixed in with the hydraulic pressure during a stop period in which the supply valve and the pressure reducing valve are closed is estimated. And a correction unit that corrects the amount of pressure oil supplied to the hydraulic chamber when the supply valve is opened again by reopening the supply valve based on the estimation result of the estimation unit. And when the hydraulic pressure of the hydraulic circuit exceeds a predetermined upper limit hydraulic pressure by correcting the amount of pressure oil to be supplied to the hydraulic chamber by the correction means at the time of restart for supplying the pressure oil again, A hydraulic pressure limiter that opens the pressure reducing valve to reduce the hydraulic pressure of the hydraulic circuit at the time of restart, and the hydraulic pressure limiter obtains the valve opening current based on the hydraulic pressure of the hydraulic circuit and the upper limit hydraulic pressure It is comprised so that it may be comprised.
[0008]
[0009]
Further, according to the present invention, in the above invention, the correction means includes means for increasing the amount of pressure oil supplied to the hydraulic chamber at the time of restart as the air mixing amount estimated by the estimation means increases. A hydraulic control device including the hydraulic control device.
[0010]
Still further, according to the present invention, in any one of the above-described inventions, the estimation unit includes a unit that estimates an amount of air contamination based on the stop period and estimates a larger amount of mixture as the stop period is longer. Is a hydraulic control device characterized by
[0010]
Furthermore, the present invention provides the correction means according to any one of the above inventions.

Claims (6)

In a hydraulic control device configured to open a supply valve and supply pressure oil from a hydraulic source to a hydraulic chamber that performs a predetermined operation by supplying pressure oil,
Estimating means for estimating an amount of air mixed into the hydraulic pressure during a stop period in which the supply valve is closed;
Correction means for correcting the amount of pressure oil supplied to the hydraulic chamber when the supply valve is reopened and pressure oil is supplied to the hydraulic chamber again based on an estimation result by the estimation means. A hydraulic control device characterized by comprising: A pressure reducing valve for reducing the hydraulic pressure of a hydraulic circuit for supplying pressure oil to the hydraulic chamber;
When the hydraulic pressure of the hydraulic circuit exceeds a predetermined upper limit hydraulic pressure by correcting the amount of pressure oil supplied to the hydraulic chamber by the correction means at the time of restart for supplying the pressure oil again, The hydraulic control device according to claim 1, further comprising a hydraulic pressure limiting unit that opens the pressure reducing valve to reduce a hydraulic pressure of the hydraulic circuit.   The said correction | amendment means contains a means to increase the quantity of the pressure oil supplied to the said hydraulic chamber at the time of the said restart, so that there are many amounts of the air mixture estimated by the said estimation means. Hydraulic control device according to.   The said estimation means includes a means to estimate the amount of mixing of air based on the said stop period, and to estimate the amount of mixing more as the stop period is longer. Hydraulic control device.   The apparatus further comprises secondary correction means for correcting the amount of the pressure oil corrected by the correction means based on any of an oil temperature, an outside air pressure, and a state of deterioration of the hydraulic pressure. Item 5. The hydraulic control device according to any one of Items 1 to 4. The hydraulic chamber is provided in a transmission mechanism that sets a transmission torque capacity in accordance with the supplied hydraulic pressure, and is determined based on the air mixing amount estimated by the estimation means, and is supplied to the hydraulic chamber at the time of restart. Torque correction means for reducing the torque input to the transmission mechanism when the correction amount of the pressure oil that can be corrected by the correction means is insufficient with respect to the correction amount of the pressure oil to be The hydraulic control device according to claim 1, wherein the hydraulic control device is provided.

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